Adenomyosis

Adenomyosis is a gynecologic disorder in which endometrial glands and stroma are found within the myometrium, the muscular wall of the uterus. The ectopic endometrial tissue responds to hormonal cycles, often causing uterine enlargement, tenderness, and symptoms such as pelvic pain and heavy menstrual bleeding.

Symptoms range from none to severe. The most common complaints are dysmenorrhea (painful periods), menorrhagia (excessive menstrual bleeding), chronic pelvic pain, and dyspareunia. Some individuals experience infertility or pregnancy-related complications, while others have a normal course. The severity does not always correlate with the extent of disease on imaging.

Epidemiology and risk factors are not precisely defined due to diagnostic variability. Adenomyosis typically affects women in their 40s and those who have had pregnancies. Risk factors include prior uterine surgery or instrumentation, parity, and a history of endometriosis. The condition is often diagnosed incidentally or during evaluation for symptoms; many cases are identified only after hysterectomy when tissue is examined histologically.

Pathophysiology is not fully understood. Theories include invasion of endometrial tissue into the myometrium, hyperplasia or hypertrophy of the myometrium in response to the altered architecture, and inflammatory or remodeling processes. Adenomyosis can be diffuse, producing widespread thickening of the myometrium, or focal, presenting as an adenomyoma. It can coexist with endometriosis.

Diagnosis relies on clinical suspicion supported by imaging. Transvaginal ultrasound and magnetic resonance imaging can reveal thickened junctional zone, myometrial dysplasia, or focal nodules. MRI is the most accurate noninvasive modality; definitive histology is usually obtained only in surgical specimens.

Treatment is individualized to symptoms and fertility plans. Management ranges from analgesics and hormonal therapies (nonsteroidal anti-inflammatory drugs, combined oral contraceptives, progestins, levonorgestrel intrauterine system, or GnRH agonists) to uterine-sparing procedures (focused ultrasound, MRI-guided thermal ablation, or embolization) and, for definitive management, hysterectomy. Fertility can be affected, but pregnancy is possible in some cases. Prognosis varies with symptom burden and response to therapy.